1. Field of the Invention
This invention pertains to the field of the protection of transformers in the presence of high voltages in a common mode/differentiated configuration. A particularly useful application for this invention is in the field of protecting the power supply transformer of a traveling wave tube amplifier (TWTA).
2. Description of the Prior Art
A prior art search uncovered the following U.S. patent references:
U.S. Pat. No. 2,680,209 shows in FIG. 7 a choke (unlabeled) which transfers the voltage from the heater transformer in a klystron to the choke itself. This device is useful only when the voltage supplied to the cathode (12') is pulsed voltage. The present invention, on the other hand, accommodates non-pulsed voltages including d.c. voltages as well as pulsed voltages. Furthermore, in the '209 patent, all the voltage drop is placed across the choke, whereas the present invention spreads the voltage between two transformers or among several transformers.
U.S. Pat. No. 2,599,890 shows a circuit for isolating heater transformer 18, 19 from the high voltage applied to the cathode in a magnetron by means of using chokes 16 and 17. As in the '209 patent, the voltage supplied to cathode 12 is a pulse, applied at terminal 13 via capacitor 20. The present invention accommodates non-pulsed as well as pulsed high voltages. Furthermore, the '890 patent develops the full voltage drop across chokes 16 and 17, whereas the present invention spreads voltage stress between two transformers or among several transformers.
Secondary references are: U.S. Pat. Nos. 1,586,162; 2,151,786; and 3,376,491.